30A JB's and 32A ring final circuits

[Farmelectrics]

Finish the job and try not to work with the guy again

 

[rattlehead85]

A J.B under a floor is deemed inaccessible especially for inspection and testing purposes mainly because an inspector will not reasonably know where such a box is situated unless suitable plans and drawings are provided with the installation which in reality is NEVER!!

 

[Tiny Spark]

not an option unfortunatly, i would if i had my way join with crimps in a box all the time, but this guy has for some reason got something against crimps and complains any time he see's them
(he gives me the work but it is council work and i see it as a waste of my council tax some of the lengths he goes to)

Sounds like the guy is very set in his ways.
Personally I love crimps and would rather them to a JB.
If I do have to use a form of JB I would prefer a waygo type (not sure thats how you spell it but you know the maintenance free type)

As for the accessible thing it is open to interpretation, But I think its the same as most other things in this trade whereby you have to use a little common sense and take it with a pinch of salt.

I would say if you need to damage something (pulling up boards for instance) then its not accessible.
I think it should be accessible with only basic tools and have enough room around it to be able to work on it.

 

[Guitarist]

JB under floorboards covered by carpet is inaccessible, simple.
Using JB's in this day and age when we have Wagos and lineproducts....Inexcusable. Why even argue the point when we have quick and easy MF kits available.

 

[ExArmy]

under the floor is not accessible. what happens when someone puts down laminate, vinyl or glued down lino??

 

[ExArmy]

JB under floorboards covered by carpet is inaccessible, simple.
Using JB's in this day and age when we have Wagos and lineproducts....Inexcusable. Why even argue the point when we have quick and easy MF kits available.

why indeed, wagos are much quicker and easier to install! and i don't pay for them, the customer does, not that it matters as the labour saving evens it out

 

[jamesBoater]

a also if 30A JB's were not sufficient why do wholesalers not stock a 32A jb?

wholesalers do stock 32 amp Junction boxes we use the Hager MF ones when needed.

 

[MDJ]

ive been having a dispute with another electrician about using 30A JB's on rings

a ring is made up of 2 legs of 2.5mm T+E,
2.5mm T+E ref method C has current carrying capacity of 27A

now surely the JB has to be rated higher than the cable, but using a 30A jb although this is less than the 32A MCB its only joining one half of the circuit and is still higher than the rating of the cable
the arguement is that he thinks i should be using 45A JB's as they are rated above the MCB

whats peoples feeling on this matter as this is the first electrician ive met in 10 years that ever had a problem joining a ring with 30A JB's

i also did a little reasearch and although i couldnt find the correct reference in the regs book wikipedia stated that the cable size in a ring should be rated at no less than 2/3 ( two thirds) of the MCB
meaning that the cable rating has to at least be 21.333A so a 30A jb would be sufficient by 8.66A

a also if 30A JB's were not sufficient why do wholesalers not stock a 32A jb?

You only join one leg though in the JB and that's rated at nowhere near 32amp???

 

[rattlehead85]

under the floor is not accessible. what happens when someone puts down laminate, vinyl or glued down lino??

Then your stuffed if a fault appears. Hammer and Chisel and an angry tenant is the scenario.

 

[elliot123]

Going back since when did metal back boxes not have to be earthed? Only an apprentice but have always been taught earth my back boxes college and onsite

 

[Guitarist]

Going back since when did metal back boxes not have to be earthed? Only an apprentice but have always been taught earth my back boxes college and onsite

If a backbox has at least 1 fixed lug, then it does not need to be earthed. That said, I always do, as do many "old school" electricians.

 

[elliot123]

Spouse you learn something new everyday, only takes a minute extra to put a earth in so won't stop

 

[telectrix]

that came in round about 2004 or a bit before. under 16th. still good practice to fit a fly lead though.

 

[Guitarist]

Spouse you learn something new everyday, only takes a minute extra to put a earth in so won't stop

Not sure that I like being called your spouse.... My wife may have something to say about that....

 

[Guitarist]

that came in round about 2004 or a bit before. under 16th. still good practice to fit a fly lead though.

Indeed.